1. Field of the Invention
This invention relates to heating and cooling apparatus.
More particularly, this invention relates to heating and cooling apparatus for use in combination with structures.
In a further and more specific aspect, the instant invention relates to a heating and cooling unit for maintaining an environment enclosed by a structure at a selectively desired comfort range.
2. Prior Art
Air-conditioning is normally defined as the control of temperature, humidity, purity, and motion of air in an enclosed space, independent of outside conditions. There exist a variety of apparatus and methods to control the environmental conditions of an enclosed space, stemming from the primitive means of hanging wet grass mats over windows for cooling air by evaporation, to more advanced techniques that employ more sophisticated air-conditioning technology.
For instance, in a simple air conditioner, a refrigerant, normally consisting of Freons (carbon compounds containing fluorine and chlorine or bromine), in a volatile liquid form, is passed through a set of evaporator coils across which air inside a room or enclosed space is passed. The refrigerant evaporates and, in the process, absorbs the heat contained in the air. When the cooled air reaches its saturation point, its moisture content condenses on fins placed over the coils. The water runs down the fins and drains. The cooled and dehumidified air is returned into the room by means of a blower. During this process, the vaporized refrigerant passes into a compressor where it is pressurized and forced through condenser coils, which are in contact with the outside air. Under these conditions, the refrigerant condenses back into a liquid form and gives off the heat it absorbed inside the enclosed space. This heated air is expelled to the outside, and the liquid recirculates to the evaporator coils to continue the cooling process. In some units, the two sets of coils can reverse functions so that in winter, the inside coils condense the refrigerant and heat rather than cool the room or enclosed space. Such a unit is typically referred to as a heat pump.
Although air-conditioning units of these types are exemplary, they are expensive to operate as they use a tremendous amount of electrical power, and the refrigerant must be periodically replaced or replenished. Furthermore, the chemicals used in air conditioners contain chlorofluorocarbons, which are proven harmful to humans and the environment. Additionally, air-conditioner units typically recirculate the air in an enclosed structure, and the recirculated air eventually becomes stale and impure over time.
Another system of cooling air in an enclosed space is simply by means of passing air through water for cooling the air by means of evaporation. The apparatus used for accomplishing this method of cooling are normally referred to as evaporative coolers. Although evaporative coolers are less expensive to operate than the air conditioners that use refrigerant as discussed above, and they do not recirculate the air as do the air conditioners, they are not very effective when the 1% coincident wet bulb temperatures are high. Thus, although evaporative coolers are less costly to operate, air-conditioning units are more effective at higher 1% coincident wet bulb temperatures. Furthermore, over time, evaporative coolers tend to use lots of water, and provide a buildup of humidity within the structure which can lead to mildew buildup, and an annoying mildew smell. In order to attain relief, windows in the structure must be opened to release the humid air, or relief vents can be provided for expelling the humid air.
Accordingly, many structures have both an air-conditioning apparatus, and an evaporative cooling apparatus, both of which are used for cooling the internal areas of the structure. However, in order to have both an air-conditioning unit and an evaporative cooler, both must be separately purchased, which is not only very expensive, but also inconvenient and time consuming to install. Additionally, when both an air-conditioning unit and an evaporative cooler unit are installed in combination with a structure, two penetrations into the structure are required which lead into two different sets of duct systems which also must be constructed at considerable cost. A further inconvenience of having both an air-conditioning unit and an evaporative cooler unit is that in order to switch use from one or the other as selectively desired, it must be done manually by either physically adjusting the individual units, or by means of a manual switch located apart from the individual units and normally within the structure.
Some cooling units include both an air-conditioning unit and an evaporative cooler unit that contains a damper and actuator mechanism that moves the damper back and forth from operation of the air-conditioning unit and the evaporative cooler unit, and through the manual operation of a remote control position switch. However, not only is it inconvenient to have to manually operate the remote control position switch, it is not always readily apparent to the user when it is more cost effective and efficient to switch from either the air-conditioner unit or the evaporative cooler to the other.
Alternate systems of cooling include the use of chilled water. Water may be cooled by refrigerant at a central location and run through coils at other places. Water may be sprayed over glass fibers and air blown through it. Dehumidification is achieved in some systems by passing the air through silica gel which absorbs the moisture, and in others, liquid absorbents cause dehydration. Although these systems are exemplary, they use a tremendous amount of water, which can not only be expensive, but not very practical for dryer regions where water is less abundant.
The specific design of air-conditioning systems normally requires the consideration of a variety of variables and circumstances. For instance, some of the self-contained units, described above, serve an enclosed space directly. More complex systems, as in tall or large buildings, use ducts to deliver the cooled air. In the induction system, air is cooled once at a central plant, and then conveyed to individual units, where water is used to adjust the air temperature according to such variables as sunlight exposure and shade. In the dual-duct system, warm air and cool air travel through separate ducts and are mixed to reach a desired temperature. A simpler means of controlling temperature is to regulate the amount of cold air supplied, cutting it off once a desired temperature is reached. Since these types of systems require two distinct sets of ducts, one for carrying cool air and one for carrying warm air, they are normally very expensive to manufacture as a result of the requirement of having two sets of ducts, and very expensive to maintain.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
Accordingly, it is an object of the present invention to provide a new and improved apparatus for heating and cooling.
Another object of the present invention is to conserve utilities.
And another object of the present invention is apparatus for heating and cooling that is relatively inexpensive to manufacture.
Still another object of the present invention is to provide an apparatus for heating and cooling having an automatic switching mechanism for selectively and automatically switching operation of the unit between air conditioning and evaporative cooling when the environmental conditions provide use of one is more efficient and cost effective than the other.
Yet another object of the instant invention is to eliminate the need for multiple penetrations through a structure, and the need for multiple duct systems.
Yet still another object of the instant invention is to eliminate the need for a user to purchase separate air conditioning and evaporative cooler units.
And a further object of the invention is eliminate the need for opening windows for relieving a structure of humid or stale air.
Still a further object of the immediate invention is to provide a heating and cooling unit that uses a common duct system.
Yet a further object of the invention is reduce energy costs associated with heating and cooling.
And still a further object of the invention is to provide a heating and cooling unit that is easily installed, and easily accessible for servicing and repair.